Propellent powder and process of making same



UNITED STATES PATENT OFFICE.

CLARENCE I. B. HENNING, OF WILMINGTON, DELAWABE, ASSIGNOB TO E. I. DU PON'I. DI:

NEHOUBS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELA- PBOPELLENT POWDER AND PROCESS OF MAKING SAME.

Patented Apr. 13, 1920.

WARE.

1,336,463, Specification 01' Letters Patent. 80 Drawing. Application filed August 28, 1919. Serial No. 819,485. F

To allwhom it may concern:

Be it known'that I, CLARENCE I. B. HEN- nvo, a citizen of the United States, and a resident of .lVilmington, in the county of New Castle and State of Delaware, have invented a certain new and useful Propellent Powder and Process of Makin Same, of which the followin is a speci cation.

This invention relates to propellent powder compositions containing constituents capable of counteractin metallic fouling, and to a process of ma ing such compositions.

Metallic fouling of the bore of small arms and ordnance, particularly military rifles and military guns, which is caused by the fusing of the metal from the projectile with the steel of the gun barrel, has for many years been a source of trouble.

It is well known that the introduction of breech loading in arms of all kinds subsequently led to giving rotation to the projectile by means of riflin with twists. .As the chamber of the gun is larger than the bore, the projectile is provided with a soft metal band, usually of copper. When the combustion of the propellent powder causes the projectile to move forward, the bands of the projectile which conform in shape to the section of the rifling assure the pro r.rotatioir to the project1le. As the ban completely fills the cross section of the bore it also serves as a check to prevent the escape of gas past the projectile and in addition it serves to center the projectile in the bore and to determine a fixed position of the projectile when rammed in the gun. During the passage of the projectile through the bore of the gun the copper from the band fuses with the steel of the bore of the 11, due to the high temperature. This fou ing of the bore of the gun is usually referred to as metallic fouling and the amount increases very rapidly as additional rounds are fired in the gun and soon reaches a point where the accumulated metallic fouling seriously affects the accuracy of the gun and also reduces the diameter of the boreof the n to a point where the continued use of t e gun is very dangerous because of developing too high pressure. It is, there fore, necessary after a relatively small -number of rounds have been fired to either rebore or re-line the gun.

In the case of small arms, as for example military rifles, a very similar metallic fouling takes place, which is caused by the fusing of the cupro-nickel of the bullet with the steel of the bore of the rifle barrel. This metallic fouling very seriously affects the accuracy of the rifle and necessitates constant cleaning with chemicals, usually referred to as doping, for the purpose of dissolving out'the metallic fouling from the bore of the rifle.

This metallic fouling may be reduced to a certain extent by introducing-into the cartridge or cartridge bag, together with the propellent charge, a small amount of metal in the form of foil or thin strips. The metals which have given the most satisfactory results are tin, alloys of tin and lead, with or without the addition of zinc. The explanation of the removal of the metallic fouling in this way is that alloys of copper and tin are extremely brittle at elevated temperatures and do not adhere to the bore of the gun as the copper does whenfused with the steel in the absence of tin. When an alloy of tin andlead is used the alloy apparently breaks up at the time of combustion of the propellant into two components, the tin uniting with the copper in the bore of the gun to form an alloy which is extremely brittle and does not adhere to the steel. The lead apparently does not unite with the copper but acts simply as a lubricant for the succeeding rounds and tends to granulate the copper alloy and facilitate its removal.

Exhaustive tests have shown that the method of using an alloy of tin and lead in the manner above described. is a very effective means of not only reducing the metallic fouling of the gun but also of remoY- ing metallic fouling already formed. This makes it possible to use the alloy only occasionally for the removal of metallic fouling whenever it has reached a very bad condition rather than to usethe alloy contmuously for keeping down the amount of me tallic fouling.

There are a number of serious objections,

ill

quent metallic fouling by adding a metal or an alloy to the propellent change in the form of foil or thin strips. It is necessary to put the metal or alloy into separate packa 'es and add these to the cartridge or cartridge bags in the amountdesired. This involves several additional operations in the preparation of the ammunition. Due to the carelessness of the workmen the metal may be either entirely omitted from a charge or too much placed in the charge. The most important objection, however, is that the metal or alloy is not uniformly distributed throu bout the propellent charge and conse- %y the removal of the metallic fouling is not uniform throughout the bore of the un. h I have discovered that if the metal or mixture of metals or alloy for reducing or removing the metallic fouling be first finely powdered and then incorporated in the nitrocellulose or nitrocellulose-nitroglycerin colloid during the process of manufacture of the powder, a uniform distribution of the metal or alloy throughout the powder will be insured and the use of this powder will be found to reduce the metallic fouling to one-third or one-fourth of the usual metallic fouling occurring when using powder without addition of a metal or alloy. Furthermore, the smaller amount of metallic fouling which is formed in the bore of the rifle or gun will be found to be more uniformly distributed. in view of the fact that the metal or alloy isuniformly distributed throughout the propellent powder. This more uniform distribution of the metallic fouling in the bore of the gun, taken with the smaller amount of metallic fouling formed,

decidedly improves the accuracy of the gun and increases its useful life.

The object of this improved method is not so much to reduce the metallic fouling already formed in the gun,whi(-l'1 incidentally can be accomplished by the use of powder of the composition herein set forth, but more especially to prevent as much as possible the occurrence of metallic foulin by having always present iii the prope lent charge a small amount of metal or alloy uniformly distributed throughout the powder grains. In addition to the material reduclion in the amount of metallic fouling it has been found tliat the muzzle flash is very much reduced, caused by the cooling effect of the metal or alloy on the gases.

' No diiliculty in the anufacture of powder is caused by the ad itional step of incorporating finely 1)o\\'rle1'edmetal or al loy therein. The only requisite is to have the material powdered sufficiently line to pass readily through the steel wire screens used for screening the foreign particles from the mtromdlulos or nitrocelulose-nitroglycerin colloid made in lhe usi al manner and also to pass readily through the dies used to form the powder strings prior to cutting into grains. The requisite fineness of the powdered metal or alloy will of course depend somewhat upon the size of the powder to be made, but I have found, for example, that powdered tin which will pass through an SO-mesh screen is sufficiently fine for use in the usual sizes of rifle and cannon powders. It is obvious that powdered tin finer than SO-mesh can be used. The amount of metal or alloy required to reduce the metallic fouling of the projectile depends upon a number of factors. In the case of the reduction of the metallic fouling in the .30-cal. Springfield rifle by means of powdered tin, I have found that from about 2.5% to 5.0% of powdered tin gives very satisfactory results, depend ing on the kind of bullets and ballistic requ1r'ements. However, I do not care to limit myself to the particular percentage of powdered tin or to any particular percentages or kinds of metals or mixture of metals or alloys, which I ma desire to use because it is obvious thatIwi 1 use that amount and kind which may be readily ascertained by a test to give the best results for the particular use for which it is intended. For example, a suitable alloy of tin and lead is in the proportion of tin and lead. However, the amount of tin can be ver materially increased and the amount 0 lead decreased, if not entirely omitted, with very satisfactory results.

My new process may be illustrated by the following exam le:-

The improi'e propellent powder, containing finely powdered metal, according to my invention, can be made by the usual process for making propellent powder for small arms and ordnances. For example, sulficient wet nitrocellulose to give 100 parts by weight of nitrocellulose. which may be a mixture 'ot' nitrocellulose soluble in etheralcohol with nitrbcellulose relatively insoluble in ether-alcohol, or may be a soluble nitrocellulose alone, dehydrated with ethyl alcohol of approximately 95% by volume or 199 proof, by means of a dehydrating press, in order to displace the water. The excess alcohol is removed from the nitrocellulose leaying about 33 parts by weig t of alcohol in the dehydrated nitrocellu ose. To this is added approximately 66%; parts by weight of ethyl-ether in a suitable mixing machine, preferably provided with brine refrigeration. To the nitrocellulose and solvent in the mixer there may be added one-half or more parts of diphenylamin or other stabilizer, with 1 to 5 or more parts of the powdered metal, such as powdered tin. together with other ingredients, if desired, such as graphite, nitro-compounds, etc. The composition is thoroughly instance in small mixed and colloided, which operation in the mixer requires about hour or more, dependin on the eflicienc of the mixer. After thorough mixing, the colloided composition is formed into preliminary blocks by means of a press. These blocks are then placed in a so-called finishing press, and the composition pressed through dies into strings, which strings are granulated by means of a cutting machine. The granulated powder is then placed for one or more days in solvent recovery a paratus to recover alcohol and ether, an then dried in water or air, to reduce the solvent remainmg in the powder to a low amount. The

powder is then air dried to remove excess surface moisture an may or may not be glazed.

Although tin and zinc, and the lead alloy of tin have been mentioned specifically above as suitable metals for incor oration in the powder to counteract metal ic fouling, there may be used various other metals capable of forming with co per an alloy which is brittle at an elevate temperature.

My invention is, furthermore, not limited to powder capable of overcoming the metallic fouling in connection per, but is also applicable to cases in which the soft metal band comprises a substance other than copper either alone or in combination with copper. the 'soft metal band consists entirely of copper or not, the owdered metal or metals incor orated in tlie powder should be capable of orming with the soft metal of the and an alloy brittle at an elevated temperature and not adhering as strongly to the bore of the gun as does the soft metalalone. For arms and munitions, the with an alloy of copper according to usage in the usually 85% copper and experiments indicate that tin incorporate in the powder is eflicient in remo'vmgthe fouling from this on ronickel alloy, as well as metallic copper ouling. This is particularly important because the majo rity of military bullet is jacketed and nickel which United States is 15% nickel. -M

I claim 1. The process of producing a propellant powder capable. of counteract ng the metalprises incorporating in a prope lent owder composition a finely subdivided meta ca able of forming with said soft metal an allby which does not adhere" astenaciously to the boreof the gun at elevated temperatures as does the soft metal alone.

2. The process of producing a propellent powder capable of counteracting the metalcaused by soft metal carrie with projectiles I having a soft metalband composed of cop- In any case whether small arms car; fridges contain cupro-nickel jacket bullets.

. loiding the lie fouling of the bore of a n ordinarily caused by soft metal carriedll; the micetile to be shot from said gun, whic comprises incorporating in a pro ellent owder composition a final sub-diviiidd meta ca able of forming wit said soft metal an al oy which is brittle at elevated temperatures.

The process of producin a propellent powder capable of counteracting the metalic fouling of the bore of a n ordinarily caused by soft metal carrie by the projectile to be shot from said gun which comprises incorporating in a propellent powder composition a finely subdivided metallic substance comprising tin.

4. The process of producing a propellant ordinarily by the projectile to be shot from said gun which comprises incorporating in a ropellent powder composition a finely suivided metallic substance comprising tin and lead.

5. The process of producing nitrocellulose powder capable of counteracting the metallic fouling of the bore of a caused by soft metal carried y the projectile to be shot from said gun, which comlic fouling of the bore of a $111 ordinarily prises incorporating in a nitrocellulose powder composition during the step of colloiding the nitrocellulose a finely subdivided metalca able of forming with said soft metal an a oy which does not adhere as tenaciously to the bore of the gun at elevated temperatures as does the soft metal alone. i

6. The process of producing nitrocellulose owder capable of counteracting the metalic fouling of the bore .of a ordinarily caused b soft metal carrie by the projectile to shot from said gun, which comprises incorporating in a nitrocellulose powder composition during the step of colloiding the nitrocellulose a finely subdivided metal ca ableof formin with said soft metal an oy which is'brittle atelevated temperatures.

The process of producing nitrocellulose powder capable of counteracting the metallic foulin of the bore of a gun ordinarily caused Ey soft metal carried by the projectile to'be shot from said gun, which comprises incorporating in a nitrocellulose powder composition during the step of .colnitrocellulose a finely subdivided metallic substance comprising tin.

8. The process of producing nitrocellulose powder capable of counteractmgthe metallic fouling of the bore of a caused by soft metal carried by the projectile to be shot from said gun, which comprises incorporating in a nitrocellulose pow der composition during the step of colloiding the nitrocellulose a finely subdivided metallic substance comprising tin and lead.

gun ordinarily therethrough.

9. A ro ellent powder containing in a finely su div ded condition a metal capable of reducing metallic fouling.

10. A re ellent owder containing unifor nly distr buted t erethrough in a finely subdivid d condition a metal capable of reducing metallic fouling.

11. A propellent powder containing a finely subdiv ded metallicsubstance comprising tin uniformly distributed therethreugh.

12. A propellent powder containing from about 1 to 5% of a finely subdivided metallic substance com risin tin uniformly distributed theret roug 13. A propellant powder containing a finely subdivided metallic substance cornprismg tin and lead uniformly distributed tberethrqugh.

14. A propellent powder containing from 1 to 5% of a finely subdivided metallic substance comp isin tin and lead uniformly distributed t ere rough.

15. A nitrocellulose explosive grain containing in a finely subdivided condition a metal capable of reducing metallic fouling.

16. A nitrocellulose explosive grain containing uniformly distributed theretlirough in a finely subdivided condition a metal capable of reducin metallic fouling.

17. A nitrocel ulose explosive grain containing a finely subdivided metallic sub stance comprising tin uniformly distributed 18. A nitrocellulose explosive rain containin from about 1 to 5% of a nely subdivi e metallic substance comprising tin uni ormly distributed tlierethrough.

19.. A nitrgcellulose explosive grain con- Memes taining a finely subdivided metallic sub" stance comprisin tin and lead uniformly distributed theret rough.

20. A nitrocellulose explosive grain containing from 1 to 5% of a finely subdivided metallic substance comprising tin and lead uniformly distributed therethrough.

21. A propellent powder containing a finely subdivided metallic substance comrising about three parts of tin to 2 parts of ead uniformly distributed tlierethrough.

22. A nitrocellulose explosive grain containing uniformly distributed therethrough a finel powdere metal ca able of forming with t e soft metal carrie by a projectile which is to be propelled by the explosion of said ain, an alloy which is brittle at elevate temperatures.

23. A nitrocellulose explosive grain containing uniforml. distributed therethrougl a finely powdere metal capable of forming with copper an alloy which is brittle at elevated temperatures.

24. A nitrocellulose explosive grain containing uniformly distributed tlierethrougli from about 1 to 5% of a finely powdered metal capable of formin with the soft metal carried by a projectifie which is to be propelled by the explosion of said grain, an alloy which is brittle at elevated temperatures.

25. A nitrocellulose explosive grain containing uniformly distributed therethrough from about 1 to 5% of a finely powdered metal capable of forming with copper an alloy which is brittle at elevate temperatu .es.

n testimony whereof I afiixfilg si nature.

CLARENCE I. B. N. Ne. 

